1. Field of the Invention
The present invention relates to a burner, in particular a burner with a long flame, as is used for uniformly heating a long furnace. The invention also relates to a method for uniformly heating a long furnace. Such a burner and the corresponding method are preferably used for melting metals, in particular non-ferrous metals.
2. Related Art
DE 2004 037 620 B4, for example, discloses a burner with a variable flame length, which is operated with gaseous fuel and oxygen and the flame length of which can be set. According to the prior art, furnaces for melting metals are preferably operated with a burner at one end. This burner is usually installed at the inlet door or in the region of the inlet of the furnace, i.e. in the region of a cover. This keeps down the technical complexity and the costs, in particular in comparison with the use of a plurality of burners. For heating larger batches, longer and longer furnaces are being used. This gives rise to the disadvantage that lower temperatures may occur at the end of a furnace opposite from the burner than on the burner side. This may result in deposits of solidified or solid material, which is disadvantageous in particular when melting metals. For example, when processing an alloy, the composition is adulterated if higher-melting constituents solidify out. To avoid this, previously known burners have simply been operated with a greater throughput, i.e. both the amount of fuel fed in and the corresponding amount of oxygen have been increased. However, apart from increased noise, this leads to increased thermal loading of the components of the furnace and the lining, in particular in the region near the burner. It has not been possible to avoid a significant difference in temperature between the burner side and the opposite side.
A burner according to EP 2 166 284 A2 has also been unable to achieve this, even though, by an asymmetric flow profile, this burner makes it possible to adapt to different operating situations.
Other special burners are described in EP 0 038 257 A1 and EP 0 663 562 A2, but these also cannot ensure uniform heating of modern long furnaces.
Against this background, the present invention aims at least partially to overcome the disadvantages known from the prior art. In particular, it is intended to provide a burner and a method for operating a burner with which a long furnace can be heated largely uniformly. In particular, it is intended to achieve a greater flame length, with at the same time good, low-polluting combustion, than with burners according to the prior art.
The aim is achieved by means of a burner and a method for operating a burner as defined in the independent patent claims. Advantageous improvements, which can be used on their own or in combination with one another, are the subject of the respective dependent patent claims.